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Mangrove cuckoos are commonly found in mangrove forests throughout many parts of Florida (Hipes et al. 2001). They also inhabit tropical hammocks in the Florida Keys and nearby mainland areas. Habitat requirements are poorly known, but larger forest tracts seem to be preferred. Mangrove cuckoos avoid heavily developed areas. The winter range appears to overlap somewhat with the breeding range, but records are patchily distributed. The range- wide distribution includes the Gulf coast from northern Mexico south to Nicaragua and from central Florida to the Antilles (Hipes et al. 2001).

78 Distribution Data

The CCVI utilizes distribution data to calculate estimates of relative exposure for each species. Data considered as part of this assessment (Figure A5-1) included a range map from NatureServe (Ridgely et al. 2003), a potential habitat model (phm) developed by FWC (Endries et al. 2009) and FNAI element occurrence data (FNAI 2011). The species experts felt that the NatureServe range grossly overestimated the species' distribution. Based on this input, we decided not to use this data set in our analysis. The FWC potential habitat model was considered adequate by the reviewers, although it appeared to exclude some potential coastal upland habitats along the southwest Florida coast. Based on comments from the species experts we also used the mangrove layer and hardwood hammock habitat layer from the Florida Comprehensive Wildlife Conservation Strategy (2005) as a proxy for the species' distribution in counties with known occurrences. FNAI occurrence data included 17 records for this species, the majority of which occur in the Keys. For comparison, we also ran the analysis at a very coarse scale, using counties with known occurrences to estimate distribution (Hipes et al. 2001). Although we included the occurrence data for comparison with other distribution data, we did not specifically evaluate the how well the element occurrences approximated the range extent as part of our assessment. The Florida Breeding Bird Atlas (FWC 2003) was suggested as an alternative data set, but we did not include it in this analysis.

Exposure

We obtained downscaled data from Climate Wizard (Zganjar 2009) for the state of Florida for mid- century projections based on the mean ensemble model under the A1B emissions scenario. Moisture data, in the form of the Hamon AET: PET moisture metric was downloaded from NatureServe, and is derived from Climate Wizard temperature and precipitation projections for mid-century under the A1B emissions scenario. To use the CCVI, the percentage of the distribution that is exposed to a particular range of projected change in temperature or moisture is calculated in ArcGIS by overlaying the exposure data on the distribution or occurrence data.

For point data sets, we assigned a single exposure value to each of the points based on the overlay. Indirect Exposure

Sea level rise (B1). Experts indicated that between 90- 100% of the species' current range is expected to be inundated under a 1-meter sea level rise. In follow up discussion, experts agreed that there would likely be both loss and gain of habitat depending on the response of mangroves to sea level rise. This factor was scored as greatly increases vulnerability. However, one of the species experts referenced a modeling study suggesting that the extent of mangroves will increase as a consequence of sea level rise and subsequent invasion of freshwater marsh. We considered this alternative scenario in a separate model run in which this factor was scored as somewhat decreases vulnerability.

Potential impact of barriers on range shifts. Experts indicated that the species' habitat consists of mangrove forest throughout Florida and tropical

Figure A5-1. Distribution inputs considered for the CCVI analysis (FNAI element occurrences not shown).

79 hardwood hammock in the Keys. Due to the strong association with a restricted habitat, we took habitat into account when scoring this factor, because this is a limiting factor affecting whether the species' distribution can shift. Whether the habitat is considered vulnerable under climate change affects the scoring of the factors B2a and B2b. Therefore we have scored these factors under two different scenarios: Scenario A (mangroves vulnerable, decreasing in extent under climate change) and Scenario B (mangroves expanding under climate change).

Natural barriers (B2a). Two reviewers scored this factor as "neutral," based on NatureServe guidance that barriers do not exist for most birds (as they can fly around them). However, little is known about the migration patterns of mangrove cuckoo. Mangrove cuckoos in southern Florida may be non-migratory and more sedentary than most bird species. One expert took associations with habitat into account and scored this factor as "somewhat increases" vulnerability but with lower confidence in evaluating how readily the mangrove ecosystem will migrate inland, suggesting that upland landforms could present natural barriers to mangroves. Under Scenario A, we scored this factor relative to the impact on habitat and captured some of the uncertainty by including scores of both neutral and somewhat increases vulnerability. Under Scenario B, this factor was scored as neutral because the habitat is not considered vulnerable to climate change.

Anthropogenic barriers (B2b). Two reviewers considered the impact of anthropogenic barriers (primarily urban development in the Tampa Bay area and along the Atlantic Coast) on the potential for habitat shifts and considered that 10-25% of the range boundary would be impacted by these barriers, corresponding to a score of "somewhat increases" vulnerability. One of these reviewers also included a score of "neutral" to capture uncertainty in the magnitude of the impact of anthropogenic barriers on distributional shifts. The third reviewer scored this factor as "neutral" based on NatureServe guidance that barriers do not exist for most birds. The experts agreed that the factor should be scored as "neutral" if based only on the impact of these barriers to the focal species and not through associated habitat. Our decision in scoring this factor was to capture the indirect threat of barriers through impacts on the ability of habitat to shift. We used the reviewers’ scores of somewhat increases vulnerability for Scenario A and scored this factor as neutral under Scenario B.

Land Use Changes Resulting from Human Responses to Climate Change (B3). All three species experts mentioned shoreline hardening and seawalls as a potential factor having a negative impact on the ability of habitat to shift under climate change, but with a large amount of uncertainty surrounding the extent to which future shoreline protection would impact the species. Two reviewers scored this factor as "somewhat increases" vulnerability, to capture the threat of mitigation/adaptation-related land use changes that may occur. One reviewer also included a score of "neutral," characterizing the species as being Table A5-1. Projected temperature exposure for mangrove

cuckoo in the assessment area. The percentages are used to calculate the temperature component (ET) of the exposure

metric. See Young et al. (In press) for details.

Data set →

(Distribution) FWC phm Habitat proxy occurrences FNAI counties FNAI > 5.5°F warmer 0% 0% 0% 0% 5.1 - 5.5 °F 0% 0% 0% 0% 4.5 - 5.0 °F 0% 0% 0% 0% 3.9 - 4.4 °F 0% 0% 0% 0% < 3.9°F warmer 100% 100% 100% 100% (ET) 0.4 0.4 0.4 0.4

Table A5-2. Projected moisture exposure (based on the Hamon Index) for mangrove cuckoo in the assessment area. The percentages are used to calculate the moisture component (EM)

of the exposure stress. See Young et al. (In press) for details.

Data set →

(Distribution) FWC phm Habitat proxy occurrences FNAI counties FNAI < -0.119 (Driest) 0% 0% 0% 0% -0.119 - -0.097 20% 20% 6% 17% -0.096 - -0.074 74% 74% 94% 50% -0.073 - -0.051 6% 6% 0% 33% -0.050 - -0.028 0% 0% 0% 0% > -0.028 (No change) 0% 0% 0% 0% (EM) 1.3 1.3 1.3 1.3

80 unlikely to be affected by mitigation/adaption-related land use changes that may occur. We included both scores (somewhat increases vulnerability and neutral) under scenarios A and B.

Sensitivity

Dispersal and movement (C1). The species experts characterized the species as having good to excellent dispersal, corresponding to individuals readily moving 1-10 km (good dispersal) or more than 10 km (excellent dispersal). Species experts assumed that birds are capable of traversing the matrix but noted that little is known about the species dispersal capability, including whether the species is migratory or non-migratory. In follow up discussion, experts noted that the species is found on a number of islands, so it can be assumed that the species is capable of fairly long distance dispersal. This factor was scored as somewhat decreases and decreases vulnerability.

Historical thermal niche (C2ai). This factor is intended to approximate the species' temperature tolerance at a broad scale by looking at large-scale temperature variation that a species has experienced in the past 50 years within the assessment area. This is calculated as the difference between the highest mean monthly maximum temperature and lowest mean monthly minimum temperature for each cell. We assessed this factor using the maps provided by NatureServe. We included all scores that applied to any part of the species' range in Florida, which corresponded to scores of increases and somewhat increases vulnerability. Physiological thermal niche (C2aii). Two species experts characterized the species as showing a preference for environments towards the warmer end of the spectrum, noting the association with mangroves which are limited to subtropical areas that do not freeze. These reviewers scored this factor as "somewhat decreases" vulnerability. The third expert selected insufficient evidence, but indicated that the thermal environment was not likely to be reduced by climate change, allowing us to exclude scores associated with preferences for cool/cold environments that may be reduced under climate change. We included scores of neutral and somewhat

decreases vulnerability to capture the range of reviewer responses. The scores assigned this factor reflect the species association with mangrove forest. It is unknown whether mangrove cuckoo is directly limited by a narrow thermal tolerance.

Historical hydrologic niche (C2bi). This factor is intended to capture the species' exposure to past variation in precipitation as a proxy for tolerance to large-scale variation in precipitation. The factor is assessed by calculating the range in mean annual precipitation for the period of 1951-2006 observed across the species' distribution in the assessment area. We overlaid the species' distribution with the maps provided by NatureServe to assess this factor. Although the calculated values for variation in precipitation varied only slightly across the three distribution data sets, these minor differences range corresponded to different scores: somewhat increases vulnerability for the FWC phm, habitat proxy, and FNAI counties and increases vulnerability for the FNAI occurrence data.

Physiological hydrologic niche (C2bii). The species experts considered the dependence on mangrove forests for this factor, however there was uncertainty in whether these hydrologic requirements were likely to be significantly disrupted in a major portion of the species' range. Written comments indicated that a major source of uncertainty was related to changes in freshwater flows that could result from drier conditions and inland water management. We tried not to duplicate vulnerability directly associated with sea level rise in this factor. Two reviewers scored this factor as neutral and one reviewer selected the description associated with "somewhat decreases" vulnerability, which states that the species has "very broad moisture tolerances" or would benefit from the projected change in hydrologic regime. Under scenario A, we assigned scores of somewhat increases vulnerability and neutral to this factor, in order to capture uncertainty in whether changes in hydrologic regime would have a negative impact on mangroves.

Historical precipitation exposure

FWC phm/Habitat proxy: 49 - 60 inches FNAI counties: 48 - 60 inches

81 Under scenario B, where mangroves are assumed to increase in extent, we assigned scores of neutral and somewhat decreases vulnerability.

Impacts of Changes to Specific Disturbance Regimes (C2c). Species experts considered increased intensity of hurricanes as the major disturbance regime that might have negative impact on the amount of quality of breeding habitat. However, there was a large amount of uncertainty associated with the degree to which the disturbance regime would change and/or the impact on the species. One reviewer did not make a selection, another selected the description corresponding to "somewhat increases" vulnerability and the third included "neutral," "somewhat increases" and "increases" vulnerability. From their comments, there was no indication that reviewers thought that the projected changes in storm intensity would have a positive effect on habitat. As a result, we felt we could restrict the scores to those associated with a neutral or negative impact. We included scores of neutral, somewhat increases, and increases vulnerability for this factor.

Dependence on ice, ice-edge, or snow cover habitats (C2d). All species in Florida were scored as neutral for this factor.

Physical habitat specificity (C3). Two reviewers felt there was not enough information to assess this factor. One of these reviewers mentioned salinity requirements for mangroves, which were captured in factor C2bii and so have not been included here. The third reviewer selected the description associated with "decreases" vulnerability. Based on NatureServe guidance regarding the appropriate selection for species for which the idea of specificity to a particular geologic feature or derivative is not relevant, we have adjusted the score for this factor to somewhat decreases vulnerability.

Dependence on other species to generate habitat (C4a). Most reviewers considered some level of dependence on the few species that make up mangrove forest in Florida. There was some divergence in whether this dependence would suggest a score of neutral (required habitat is generated by "more than a few" species) or somewhat increases vulnerability (required habitat is

generated by "not more than a few" species). We included both scores for this factor.

Dietary versatility (C4b). Reviewers conveyed that there was little information available regarding diet. The Birds of North America species account was provided as a reference indicating that a range of insects and arthropods are consumed. Based on this information, this factor was given a score of neutral.

Pollinator versatility (C4c). Not applicable.

Dependence on other species for propagule dispersal (C4d). The species disperses on its own. This factor was scored as neutral.

Other interspecific interactions (C4e). Additional interspecific interactions that might affect vulner- Table A5-3. Scores assigned to factors associated with vulnerability to climate change for mangrove cuckoo in Florida. Scores shown are for Scenario A1_{, which assumes that mangroves} will be negatively impacted by climate change. Bolded factors were associated with higher levels of uncertainty by the expert reviewers. Not all scores can be assigned to all factors as indicated by dashes.

Vulnerability factor GI I SI N SD D unknown or n/a

Sea level rise • --

Natural barriers • • -- --

Anthropogenic barriers • -- --

Human responses to CC -- • •

Dispersal • •

Historical thermal niche (GIS) • • --

Physiological thermal niche • • --

Historical hydrologic niche (GIS) • --

Physiological hydrologic niche • • --

Disturbance regimes -- • • •

Ice and snow • -- --

Physical habitat specificity -- •

Biotic habitat dependence • • -- --

Dietary versatility -- • --

Biotic dispersal dependence -- • -- --

Other interactions: none -- • -- --

Genetic variation -- -- •

Phenological response -- -- •

82 ability were not identified. This factor was scored as neutral.

Measured genetic variation (C5a). Reviewers did not feel that there was enough information available to assess this factor. This factor was scored as unknown.

Occurrence of bottlenecks in recent evolutionary history (C5b). Reviewers did not feel that there was enough information available to assess this factor. The population in Florida appears to be small but it is unknown how genetically isolated the population is. This factor was scored as unknown.

Phenological response (C6). Reviewers were not aware of any research specifically assessing the correspondence between changes in seasonal dynamics and changes in the timing of phenological events. This factor was scored as unknown.

Documented or Modeled Response to Climate Change

We did not include these optional factors in the analysis.

Results

Under scenario A (which assumes that mangroves will be negatively affected by climate change), mangrove cuckoo ranked as "Moderately Vulnerable" to climate change in Florida using on the exposure parameters associated with the FWC potential habitat model, habitat proxy, or county occurrences. The species’ rank dropped to "Not Vulnerable/Presumed Stable" under scenario B, in which climate change was assumed to have neutral or somewhat positive effects on the availability of mangrove habitat.

For scenario A, many of the factors contributing to vulnerability were associated with indirect exposure in the form of sea level rise and barriers (Table A5-3). These factors were scored as having neutral or somewhat positive effects on mangroves under scenario B. For both scenarios, dependence on only a few species to generate habitat, altered disturbance regime (i.e., more intense hurricanes) and potentially incompatible human responses to climate change were identified as factors contributing to vulnerability

for this species. Only two sensitivity factors were scored as unknown.

Under scenario A, the index score was 6.1 (range [2.9, 9.3], Figure A5-2) for models parameterized with the FWC potential habitat model, habitat proxy, or county occurrences. The index flagged this species as potentially expanding its range, although this would of course depend on the availability of mangrove habitat under climate change. When mangroves were assumed likely to increase in extent (scenario B), the index score dropped into the "Presumed Stable" rank (index score: -0.3, range [-3.1, 2.5]; Figure A5-2). Results based on scenario A are shown in Figure 6 in the main report.

All four of the data sets included in Tables A5-1 and A5-2 generated identical exposure metrics, and Figure A5-2. CCVI output for mangrove cuckoo in Florida. The index score (black circle) is shown with the range of scores produced by the Monte Carlo simulation. Categorical ranks are coded by color: "Highly Vulnerable" (orange), "Moderately Vulnerable" (yellow), "Presumed Stable" (green), "Increase Likely" (dark green).

83 therefore are equivalent in terms of exposure. This is perhaps not surprising given that the fairly coarse resolution of the exposure data (approximately 15 km) and the relatively narrow distribution of this species habitat along the coast. However, the FNAI element occurrence data generated a narrower range of historical precipitation exposure (factor C2bii), resulting in a higher score for this factor. This single difference in the input parameters increased the index rank to "Highly Vulnerable" (index score: 7.4, range [4.2, 10.6]) under scenario A.

We also examined model output with natural and anthropogenic barriers scored as neutral (keeping the other scores the same as scenario A), which would be appropriate if assessment of this factor is limited to barriers to the focal species, independent of the barriers impacting habitat shifts (i.e., the approach suggested in the CCVI guidance). Under these conditions, mangrove cuckoo still scored as "Moderately Vulnerable" (FWC phm/habitat proxy), but the index score decreased to 5.0 (range [2.2, 7.8]), with 80% of the Monte Carlo runs scoring as "Moderately Vulnerable" compared with 75% under scenario A. Most birds are able to fly over or around potential obstructions; however this assumption will not capture the indirect threat of barriers through impacts on the ability of habitat to shift, which most reviewers felt was an important consideration.

The CCVI is intended to be used in combination with conservation status ranks. The global conservation status rank for mangrove cuckoo is G5. The species is ranked S3 in Florida.

Literature Cited

Endries, M., B. Stys, G. Mohr, G. Kratimenos, S. Langley, K. Root, and R. Kautz. 2009. Wildlife Habitat Conservation Needs in Florida [Technical